Biasi Diverter Valve Passing to Heating Circuit

Radiators get hot when only hot water is being used, even though heating is turned off.

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Worn diverter valve seals, Debris preventing full DHW position, Faulty diverter motor not driving fully, Incorrect diverter installation

Safety: Allow radiators to cool before handling valves or pipework.

Confirm control settings: Ensure the room thermostat and programmer are not calling for heat when testing hot water.
Observe boiler flow pipes: During DHW use, feel the CH flow pipe leaving the boiler. It should remain relatively cool; if it gets very hot, the diverter is leaking.
Engineer repair: A technician can remove and service or replace the diverter valve cartridge and check the actuator operation.

Hard 4/5

Diverter Valve Assembly

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